Well, who would have predicted this? A collection of pop songs made 40 years ago dominate both popular culture and album sales this week.

A testament to the utterly timeless quality of Abba's music is the way Mamma Mia fever has overtaken the nation once more, ten years after it first did so. The long-awaited release of the sequel film to the hit musical, "Mamma Mia - Here I Go Again", has sent sales of its soundtrack soaring and this week the album nestles comfortably at the top of the Official UK Albums chart. Tellingly this is the third Hollywood musical soundtrack in the past two years to top the charts, a curious throwback to the earliest days of the format.

If nothing else, this does mean that yet another week goes by when the other hit musical soundtrack of the year The Greatest Showman does not return to the top of the charts. Yet it is still hanging in there and slots in neatly at Number 2 behind Mamma Mia. This is itself a once in generation moment, the first time two movie soundtracks have occupied the Top 2 of the albums chart since May 1978 when Saturday Night Fever and The Stud were at 1 and 2 respectively.

Topping the main albums chart is something that the soundtrack of the original Mamma Mia movie never managed because at the time it was considered a compilation and relegated to a backwater of its own. As we noted a few weeks ago, a subtle rule tweak earlier this year explicitly allowed musical soundtracks to qualify for the main album chart. As a result, the cast recording of the first Mamma Mia movie has embarked on a chart journey of its own in the wake of the release of the sequel. This week it sits at a brand new "artist chart" peak of Number 5. Three movie soundtracks in the Top 5 hasn't happened since February 1969, when we had The Sound Of Music at 2, Yellow Submarine at 4 and The Graduate at 5. That week (February 15th) there was even a fourth movie collection in the Top 10 with the cast of Lionel Bart's Oliver at Number 10.

For the original Mamma Mia soundtrack to have runs in the Top 10 of both compilations and "proper" album chart is naturally enough pretty much without precedent given it is normally impossible for albums to jump the divide. Only one album has the strange honour of topping both charts, the identity of which I'll recount later.

The individual songs from the movie soundtrack have received some small amounts of attention, but none have quite the momentum to make a proper singles chart impact. The highest charting cut from the album is the ensemble rendition of When I Kissed The Teacher which charts at Number 91, this its first appearance despite having been released as a lead single from the album back in May. Originally the lead track on Abba's 1976 album Arrival, it was never issued as a single. Not even as a b-side.

Blue Since The Day We Parted

Ten years ago with the main soundtrack album relegated to the compilations chart, it was left to the "originals" so to speak to grab the glory. New-found Abba-mania resulted in the definitive 1992 collection Gold - Greatest Hits returning to the top of the charts for the first time since its release. Now certified as the second biggest-selling album of all time in this country, the collection returns to the upper reaches once more and this week sits at Number 7, back in the Top 10 for the first time since September 2008.

In one of those odd coincidences which pop up from time to time, the album generally regarded as the biggest selling of all time in this country is also back in the charts, Queen's Greatest Hits rising to Number 29 in what is now its 835th week on the Top 100, this the 1981 release's first visit to the Top 30 since June 2011. Its last visit to the Top 10 came in December 1991 in the wake of Freddie Mercury's death.

The elephant in the room is that in spite of all the above, Mamma Mia: Here I Go Again isn't even the biggest selling album of the week. But we'll come to that detail in due course.

Quack

Time to give the singles chart the focus of our attention, although at first glance there appears to be little happening there. As you might expect, Drake's In My Feelings remains immovable at the top of the Official UK Singles chart and duly spends a second week at Number One. At the risk of reducing this to a parade of numbers, the mathematics behind this remain fascinating. Drake's only contender is George Ezra's Shotgun which is itself posting sales numbers way in excess of anything else in the market. Drake posted 95,000 chart sales last week. Ezra lagging behind on 83,000. Yet the drop to the Number 3 single is a huge one, Jonas Blue selling just 46,000 copies and a long way from contention.

Shotgun is actually the most purchased track of the week, although in marked contrast to Drake singles of the past, In My Feelings remains not too far behind and indeed its paid-for sales take a flying leap this week with a jump from 11,000 sales to well over 31,000. Needless to say though, it is on streams that Drake dominates overall. The Official Charts Company reports the track posted 9.1m streams over the past seven days. Interestingly they contributed 63,000 chart sales to its overall total, a rough conversion ratio of almost 144 streams to 1 sale. That's significantly higher than last week's total, suggesting that this time around a far larger proportion of the streams of the track came from free sources (which contribute to chart sales at a ratio of 600:1).

Shotgun's chart sale of a reported 83,051 once more is the highest it has managed to date, this despite its brief run at the top of the charts having ended three weeks ago. This is significant, as the single has been charting continuously since the release of Ezra's Staying At Tamara's album and is now considered to be 18 weeks old. Having dipped last week, this represents a rebound thus resetting the ACR clock, a single having to post three straight weeks of decline before being relegated. That means the single will theoretically keep snapping at Drake's heels for some weeks to come. Sadly the same cannot be said for last week's Number 3 single, another former Number One, Solo by Clean Bandit and the suddenly topical Demi Lovato. That takes a 3-13 tumble after being dragged onto ACR although it remains the third most-purchased and fourth most-streamed single of the week. Alas, its sole replacement in the Top 10 isn't a newer hit but another single which has been around the block a few times already. I Like It from Cardi B and friends jumps 11-8, returning to the peak it last occupied three weeks ago.

Of the other climbs in the Top 10, the most notable is perhaps the 8-4 jump of 5 Seconds Of Summer's Youngblood. This is enough to make it their third biggest chart hit ever, trailing only their debut chart-topper She Looks So Perfect and their third single Don't Stop which reached Number 2, both hits coming in 2014.

Why Don't You Give Me A Call

Climbing into the Top 20 are two tracks with contributions from two former collaborators. Jax Jones' Ring Ring (a title it shares with an Abba song, topically enough) with Mabel on vocal duties moves 23-17 to land a new peak whilst AJ Tracey's Butterflies (with a guest vocal from Not3s) reverses a previous decline and climbs back to its Number 19 peak, a position it last scaled back in June.

The summertime vibes of M-22's First Time are helping that single climb the charts too, the single reaching a brand new peak of Number 20. It has been a protracted climb, to say the least, the track having been first released in December last year. It made the Top 100 of the Official UK Singles chart for the first time at the end of March, climbed into the Top 40 on May 17th and has spent eight of the last ten weeks bouncing around between 24 and 28. As we've seen with any number of singles this year, all good things come to those who wait, and increased airplay for the track appears to be finally paying off. M-22 are an Anglo-German production team but singer Medina is from Denmark, this her first ever international hit single after over ten years of record releases in her home country.

Body On Her

Another single which has been on a protracted journey to success is Body from Loud Luxury which can also boast a "2017" in its original release date but which only now is coming to public attention. The track from the Canadian duo hasn't had to loiter around the charts for quite as long as First Time but finally climbs into the Top 40 with a 41-26 leap on its 8th week as a Top 100 hit single.

Jangle Jangle

The highest new entry proper of the week languishes at Number 33, Love It If We Made It the new single from The 1975 and which heralds the imminent release of their new album A Brief Enquiry Into Online Relationships. It is the second Top 40 hit this year from the group, following on from Give Yourself A Try which reached Number 22 back in June. The new single takes a full two and a half minutes to reach anything resembling a hook and is rather heavier going than its predecessor. Only one The 1975 hit single has ever embarked on a chart run which has seen it climb the charts steadily, their 2013 breakthrough hit Chocolate, which climbed to Number 19.

Covfefe

Also new, but with perhaps slightly better prospects for progression, the curiously titled Fefe from 6ix9ine which boasts guest vocals from Murda Beatz and the more recognisable name of Nicki Minaj. Continuing what seems to be a trend for acts to name themselves after their social media handles, 6ix9ine is 22-year-old Brooklyn rapper Daniel Hernandez, this single his first ever commercial hit record although his debut "mixtape" Day69 registered at Number 20 on the albums chart back in February. Nicki Minaj can now claim a presence on 30 different Top 40 singles since she made her chart debut in 2010.

Don't Panic

When Panic! At The Disco's album Pray For The Wicked charted a few weeks ago, I noted that for all their consistent success in long playing form the group had not managed a Top 40 hit single since 2008. That's a duck they finally break this week as the album's second single release High Hopes finally reaps the rewards of airplay from still loyal rock stations and climbs to Number 37, taking them into the relatively higher reaches for the first time since Nine In The Afternoon reached Number 13 a little over ten years ago.

Have A Shave Woman

Given that soundtrack collections are still topical, it seems appropriate to note the still evergreen chart success of This Is Me, the smash hit single from The Greatest Showman soundtrack which has given Keala Settle the biggest hit record she is almost certainly ever to put her name to. Marking 30 weeks on the singles chart this week, the single has been out of mind for some months during a wander down the Top 40 but for all that never really out of sight. This is all thanks to the extraordinary way it has continued to sell in regular quantities online, this despite a gentle slippage of its popularity at streaming and a dive to ACR a number of weeks ago. This Is Me rises to Number 28 this week, this a fortnight after slipping out of the Top 40 for the very first time. Extraordinarily it is still one of the Top 10 most-purchased singles of the moment, climbing to Number 9 on the old-fashioned sales chart. It hasn't been out of the Top 20 since its second week on release.

Now Buy It

Elephant time then, because if the Mamma Mia soundtrack isn’t the biggest selling album of the week, then what is? Unless you have been walking around with your eyes shut for the past week the answer should I hope be obvious. The milestone 100th volume in the long-running Now That's What I Call Music series was released this week, the collection of current hits and a disc of what they term "Now classics" having been greeted with a series of documentaries, think pieces and retrospective articles to make it probably the most heavily publicised hits compilation of all time. The result is a huge sale, the double album posting a chart sale of over 176,000 copies. Putting the mere 34,661 of Mamma Mia into no small degree of shade. That isn't quite enough to make it the fastest selling Now! album of recent times, however, falling short of the 202,602 copies sold by Volume 97 when it was first released a year ago. Which itself is perhaps rather telling.

Almost needless to say it is a Now That's What I Call Music album which is also the only one to have the honour of topping both "artist" and "compilations" chart, the collection in question being Volume 13 which was at the top of the market in January 1989 when the compilations chart was created, thus disqualifying all multi-artist collections from choking up the main listings they had been choking up to that point. I own that one, along with all the others released since 1983. They take up a large amount of space when you lay them all out together.